Percutaneous arterial and venous cannulation is used in a wide variety of medical procedures. For example, peripheral arterial and venous cannulation is often required for short, intermediate and long term circulatory support in patients with cardiopulmonary compromise. Extracorporeal Membrane Oxygenation (ECMO) is a form of partial cardiopulmonary bypass used for long-term support of respiratory and/or cardiac function. ECMO is primarily indicated for patients with such severe ventilation and/or oxygenation problems that they are unlikely to survive conventional mechanical ventilation. ECMO often involves shunting blood around the heart and lungs through an extracorporeal blood circuit and membrane oxygenator. Roller or centrifugal heart-lung bypass pumps are used to circulate blood through the ECMO circuit. Treatment courses can be as short as a few days or as long as a month or more.
There are different forms of ECMO such as venoarterial (VA), venovenous (VV) and arterio-venous (AV). VA ECMO takes deoxygenated blood from a central vein or the right atrium, pumps it past the oxygenator, and then returns the oxygenated blood, under pressure, to the arterial side of the circulation (typically to the aorta). This form of ECMO partially supports the cardiac output as the flow through the ECMO circuit is in addition to the normal cardiac output. Typically, patients with cardiac insufficiency require VA-ECMO. In the case of VA ECMO, an approximately 20F (6-7 mm internal diameter) arterial cannula is placed in the femoral artery, for example, but such arteries are typically much smaller, particularly in children or other smaller patients.
VV-ECMO takes blood from a large vein and returns oxygenated blood back to a large vein. Typically patient with respiratory insufficiency not amendable to ventilator support require VV-ECMO. In VV ECMO, either two large cannulas are placed in two separate extremity veins or a single dual lumen cannula is placed in one extremity. These cannulas remove blood from central circulation and return oxygenated blood to the right atrium. Often a 31F (10 mm internal diameter) cannula is placed in the internal jugular vein or the subclavian vein.
Due to the large size of the cannulas used in ECMO, the venous drainage in the extremity or head and neck region where a cannula is placed is significantly impaired. Many patients develop venous stasis, thrombosis, and edema in the extremity. Intracranial venous hypertension has been well described in the case of internal jugular vein cannulation, especially in children. On the arterial side, if a femoral artery is cannulated, the blood is often returned into the abdominal aorta and there is no perfusion to the leg on the side of cannulation. This can lead to drastic ischemic complications. Presently, if arterial cannulation is required for more than a few hours, a second smaller cannula is placed in the femoral artery for antegrade perfusion.
Accordingly, a need exists for a cannula that provides adequate proximal venous drainage and distal arterial perfusion during peripheral cannulation procedures.